#scrollUp {
  position: fixed;
  display: none;
  background-color: #777;
  color: #eee;
  font-size: 40px;
  line-height: 1;
  text-align: center;
  text-decoration: none;
  bottom: 20px;
  right: 20px;
  overflow: hidden;
  width: 46px;
  height: 46px;
  border: none;
  opacity: .8;
}

#scrollUp:hover{
  color: #eee;
  background-color: #222;
}